Case Markers

In Japanese, case markers are particles that mark nouns and noun phrases with a "grammatical case," such nominative and accusative, or subject and object.

In Japanese, case marking particles are called kaku-joshi 格助詞.

List

For reference, a list of case marking particles, the names of their respective cases, and the abbreviations found in literature.^{(data from Shibatani et al. 1982, as cited in Chien, 2016)}

ga が
Nominative case. NOM.
The subject.
wo を
Accusative case. ACC.
The object.
ni に
Dative case.
The recipient of an action.
In some cases, the dative subject.
See: double subject constructions.
de で
Instrumental case. INS.
The instrument, tool, or method, used to perform an action.
de で and ni に.
Locative case. LOC.
The location where an action occurs or where something is.
See: de で vs. ni に.
e へ and ni に.
Lative case. LAT.
The direction toward which an action occurs.
See: e へ vs. ni に.
kara から
Ablative case. ABL.
The point from where an action occurs or begins, the origin, or source.
to と
Comitative case. COM.
Together with whom an action occurs. Who accompanies the subject in the action.
no の
Genitive case. GEN.
Often creates possessive adjectives, but also creates all sorts of other adjectives, too.
See: no-adjectives.
Sometimes used to create a genitive subject.
See: no の subject marker.

Note that some particles can mark multiple cases, and some cases can be marked by multiple particles. Many particles have functions beyond case-marking, like parallel-marking, for example.

Also note that the wa は particle isn't in the list above, despite marking the topic. That's because, in Japanese grammar, wa は is categorized as a kakari-joshi 係助詞, and not as a kaku-joshi.

In Japanese, a noun marked by wo を is simply said to have the "wo case," or wo-kaku ヲ格. They don't use weird terms like "accusative case." This means a noun marked by ni に is always said to have the "ni case," ni-kaku ニ格, regardless of whether it's the dative, locative, or lative case.

Grammar

There doesn't seem to be much in common between case-marking particles besides the fact that you can only use the same case-marking particle once per clause. In a simple sentence, that's once per sentence.

For example, let's say we have this phrase:

banana wo taberu
バナナを食べる
To eat a banana.

Above, the noun banana is marked in the accusative case, so it's our object.

Now, what if we wanted to say "to eat a banana and an apple?" We're eating two things, so we have two objects, right?

*banana wo ringo wo taberu
~~バナナをリンゴを食べる~~
(no.)

When you have a situation like this, you don't mark two separate nouns with the same case. Instead, you join the two separate nouns into one big noun phrase, and then you mark the one big noun phrase with just one accusative case.^{(Kato 加藤, 2006, p. 23)}

{banana to ringo} wo taberu
バナナとリンゴを食べる
To eat {a banana and an apple}.

In the sentence above, {banana to ringo} is a noun phrase marked in the accusative case, and also the only thing marked in the accusative case, so it's alright.

Given this, the basic gist is that you can't use the same particle twice in one existence, except that's not exactly true.

First, you can use the same particle twice if it's in two different clauses.

{banana wo tabeta} basho wo wasureta
バナナを食べた場所を忘れた
[I] forgot the place [where] {[I] ate the banana}.
- Here, one wo is for the verb taberu, while one wo is for the verb wasureru.

Second, some particles can mark multiple, different cases, so they can be used once for each case.

gakkou de sumaho de asonda
学校でスマホで遊んだ
At school, with a smartphone, had fun.
Played with the smartphone at school.
- School - where the fun happens, locative case.
- Smartphone - the instrument with which the fun happens, instrumental case.

Third, the ga が particle can, in unlikely situations, show up twice. This is a double subject construction, where the first ga が is the "large subject" and the second one is the "small subject." No, I'm not making this up.

Since the large subject and the small subject perform different functions in the sentence despite being fundamentally the same thing, that is, since they aren't exactly the same thing, it's like if it were a different case, so the usage becomes valid.

zou ga {hana ga nagai}
象が鼻が長い
{Long is true about noses} is true about elephants.
{Noses are long} is true about elephants.
Elephants have long noses.